The present invention refers to a device for assembling and disassembling a sensor in bearing unit, particularly a rotation sensor in a bearing unit or a hub-bearing unit of a motor vehicle wheel.
Conventionally, in order to detect relative rotation between the rotating race and the stationary race of a unit of the above-mentioned type, detecting devices are used comprising an impulse ring mounted onto a rotating part of the unit, and a sensor that is fitted to a stationary part in a position facing the impulse ring at a preset distance. Electric signals generated by the sensor owing to the rotation of the impulse ring are transmitted to a processing unit mounted on board of the vehicle, which provides information on the speed of the wheels.
With most arrangements used to date, the sensor is incorporated in an annular body of plastic material over-moulded on an annular insert that is forcefully mounted on a surface of the non-rotating race of the hub-bearing unit.
This arrangement involves a practical drawback. When it is necessary to replace or service the sensor, the metallic insert has to be disassembled from the non-rotating race of the bearing, which is not easy owing to the afore-mentioned forced coupling. In some instances, removal of the metal insert is so difficult that one prefers to replace the whole bearing.